SOLUTION: A file cabinet contains 3 blue and 6 red folders. If folders are randomly selected, "without replacement", what is the probability of selecting:
A. Two red folders?
B. Three blue
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-> SOLUTION: A file cabinet contains 3 blue and 6 red folders. If folders are randomly selected, "without replacement", what is the probability of selecting:
A. Two red folders?
B. Three blue
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Question 342868: A file cabinet contains 3 blue and 6 red folders. If folders are randomly selected, "without replacement", what is the probability of selecting:
A. Two red folders?
B. Three blue folders?
C. The first folder blue and the second folder red?
D. A red and a blue folder?
I got:
A: 2/9= 22.22%
B: 3/7= 42.85%
C: 0 (because the blue folders were taken out with replacement?)
D: 0 (because again, there are no blue folders left?) Answer by edjones(8007) (Show Source):
You can put this solution on YOUR website! There is replacement between questions!
.
A: 6/9 * 5/8 = 5/12 or .4167
.
B: 3/9 * 2/8 * 1/7 = 1/84
OR
nCr=combination or n things taken r at a time.= n!/((n-r)!r!) (easier with larger numbers.)
3C3/9C3 = 1/84
.
C: 3/9 * 6/8 = 1/4
.
D: (6C1 + 3C1)/9C2
(6+3)/36 = 1/4
.
Ed
